Strain insulator



y 1931; w. H. KEMPTON 1,806,294

STRKIN INSULATOR Filed April 6, 1927 Z /s Q 4w fiA /4 S /4 5 /2WITNESSES: k9 INVENTUR h J/ara h Mempfd/z Patented May 19, 1931 UNITEDSTATES PATENT orrlc'n- WILLABJ) H. KEMPTON, OF WILKINSBURG,PENNSYLVANIA, ASSIGNOR TO WESTING- HOUSE ELECTRIC & MANUFACTURINGCOMPANY, A CORPORATION OF PENNSYL- VAN IA STRAIN INSULATOR Applicationfiled Apri1'6, 1927. Serial No. 181,326.

I My invention relates to strain insulators, and particularly to straininsulators embodya ing interlinked metal parts.

One object of my invention is to provide an insulator of theabove-indicated character vide a strain insulator that shall. have nocurved or other parts likely to become distorted under strain.

Another object of my invention is to provide a strain insulator,embodying an in .sulating shell or cover, that shall be so'constructedas to avoid fracturing the shell under of the blocks 2 comprises arectangular metal load conditions.

Another object of my invention is to provide a strain insulator thatshall embody novel anchoring meansfor a molded insulate ing coverthereof.

In practicing my invention, I provide an insulator of such constructionthat certain of its parts may be suited to quantity production, bycuttingthem from bars; that permits ready assembly of its parts; thatresolves its. 1 strains into straight lines to prevent fracans ture' ofits insulation and is otherwise constituted to be a material improvementover in Fig. ,1,

Fig. 3 is aside view, partially in section and partially in elevation,of the structure shownin Figs. 1 and 2, taken at right angles to Fig. 2,

Figs. 4 and 5 are detail perspective views ofparts embodied in theinsulator of the foregoing figures, and

Fig. 6 is a view, similar to Fig. 3, of a modified form of theinvention.

Referring to Figs. 1 to 5, inclusive, the insulator comprises, ingeneral, rectangular or oblong block elements 2, terminal member-s3, aloop or interlinking metal member 4 and a molded insulating cover member5.

The block elements 2, together with the terminal members 3, constituteterminal structures of substantially T-shape, or oppositelyprojectingterminals having enlarged inner ends, in .which the enlarged inner endsor heads are disposed in substantially parallel relation and surroundedby the inter-linking member 4 through which the legsof the T- structureextend. i

As more clearly illustrated in Fig. 5, each core or anchor member 7 anda substantially tubular insulating cover 8 that is preferably molded inposition and constructed of laminations or layers of paper or othersuitable sheet insulating material impregnated with a hard moldingmaterial. As thus constructed, the

blocks 2 may be readily cut from relatively long bars ofthe rectangularmetal cores on which the molded insulating cover 8 has been placed.

Before or after cutting the above-mentioned bars, holes or openingslOmaybe drilled and tapped for the reception of screwthreaded shankportions 11 oftheterminal members 3. v i

The interlinking member 4 is of substantially tubular construction,whereby it may also be cut from greater lengths of such tubing, and ispreferably of such rectangular cross-sectional area as to effect a neatsliding or press fit with two of the blocks 2.

The member 4 is further provided with oppositely disposed side openings12 0f appreciably larger diameterthan the shanks 11 and has bevelededges 14 constituting holding or anchoring portions for "assisting inholding the molded insulating body or cover 5 in position.

In constructing the insulator, the blocks 2 are pressed or passedthrough an end of the sulating body or cover'5 .is molded in position,

During the molding operation, the mate rial of the body 5 is pressedinto the spaces, in the openings 12, between the' member :4 and theterminalmembers 8. Al so,'b0sses '16 are formed'in the cover havingnotches 17 therein that cooperate with the ends of pins 18, extendingthrough the terminal members 3, to prevent turning,or unscrewing, of theshanks 11 from the blocks 2.

In the above-described structure, only 'th sides of the cores 7 arecovered by thelaminated insulating bodies 8, the ends of the coremembers and the entire'insulator being covered by theinsulatingbody' 5.This feature provides insulation that is, very strong mechanically andelectrically,

tive insulating protection for the'insulator in a simple, economicalmanner.

f Also, in the above described structure, the

hat right angular relation of'the' stressed Iparts eliminate thecollapsing tendency of curved parts in'strain devices of this character.This tendency results in fracture and dislocation of'the parts,vparticularly of the insulation which is thereby very readily renderedunfit for service and causes breakdown of the insulator.

, 'In my device, the insulating bodies 8 are substantially in straightcompression, and

V the'insulating cover 5 is practically freeof mechanical stresses ofany kind. I

In the modification ofmy invention shown in Fig. 6, in whichcorresponding parts are designated by corresponding reference charactors, the construction ,is substantially the I, same'as' that abovedescribed, eX'ceptf thatthe different form and: an entraplate or body"20 of insulation is placed betweenthebloc'ks openings lOaredrilled'through the blocks 2, the anchoring portions 14 are of slightlyThe plate20 is preferably of laminated form, similar 'to the insulatingcovers 8 in the blocks 2. V

The anchoring portion 14,," instead of i being along the end edges ofthe member 4, as shown are disposed along the longitudinaledges fromwhich they each so project in two directions as to assistin hold- 'ingthe rightangularly related sidesof the,

cover 5 in position;

Modifications and rearrangements of the portions 14: maybegmade-to holdthe molded. cover '5 in any desired'm'anner.

tubular metal member and said terminal portions and about said parts.

V where such "in 'sulation is most needed, and a general efi'ec By myinvention, a strain insulator is provided that, besides being ofextremely compact, durable and effective character, facilitates andeconomizes its manufacture and has other features of improvement overinsulators heretofore employed.

While I have shown and described par-' ticular forms of my invention,changes may be eilected therein without departing from the spirit andscope thereof, as set forth in the appended claims. A

k I claim as my invention:

1. A strain insulator comprising rectangular *block elements, includingrectangular metal core members and laminated rectangulartubularinsulating coverings thereon,-disposed in adjacent flat-surfacerelation, a rectangular tubular metal membersurrounding the elements,terminal portions I projecting from the core members through saidcoverings and through said tubular metal member in spaced relation tothe latter, and-a of insulation molded in the spaces btweenthe 2. Astrain insulator comprising rectangular block -elements,nclud1ngrectangular metal core members and rectangulartubularinsulating' coverings thereon, disposed "in adjacent flat-surfacerelation, e s for holding the elements to each other andterminal-portions projecting from the core members.

3. Astrain insulator comprisingirectangw 'lar" block elements, includingrectangular metal core members and laminated tubular insulatingcoverings of rectangularoross section molded thereon, disposed inadjacent fiat-surface relation, a tubular me'tal element of rectangularcross-section surrounding the elements, terminalmembers including shanksscrew-threadably mounted in said-=core members projecting therefromthrough said cov erings and through said tubular metal memher in spacedrelation tothelatter, and abody of insulation molded inthe spacesbetween the tubular metal member and said shanksand about said parts.

4. A strain insulator including tubular insulating portions disposed inside by-side relationtransversely to the tension" load,"

anchor members in said tubular portions, a

tubular element surrounding said tubular portions in substantiallyparallel relation thereto and terminal portions projecting through saidtubular element .'from said" anchor membersinthedirection of .said load.

5. A strain insulator including tubular insulating portions disposed inside-by-side relation transversely to the tension load,

metal anchor members in said tubular por tions, a tubular metal'elementsurrounding said tubular insulating portions in substantially parallelrelation thereto .and k-metal terminal portions projecting fromfsaidanchor members in the direction of saidload through said tubularinsulating portions and through said tubular metal element in insulatedrelation thereto.

6. An insulator including tubular insulating portions disposed inside-by-side relation,

metal anchor members in said tubular portions, a tubular elementsurrounding said tubular portions in substantially parallel relationthereto and terminal portions projecting through said element from saidanchor members transversely to the axis of said tubular element.

7. An insulator including tubular insulating portions disposed inside-by-side relation, v

, a tubular element surrounding said tubular portions in substantiallyparallel relation thereto and terminal means having anchor portions insaid tubular portions and portions extending through said elementtransversely to the axis thereof.

8. An insulator including tubular insulating portions disposed inside-by-side relation, metal anchor members filling said portions flushwith the ends thereof, a tubular metal element surrounding said portionsin substantially parallel relation thereto and having transverse wallopenings, metal ter- 'minal portions of smaller diameter than saidopenings projecting therethrough from said anchor members and a body ofmolded insulating material covering the insulator and disposed in saidopenings about said terminal portions.

9. An insulator including tubular insulata ing portions disposed inside-by-side relation and having transverse side openings, metal anchormembers in said portions having screw-threaded openings opposite saidside openings, a tubular metal element surrounding said portions insubstantially parallel relation thereto and having transverse wallopenings opposite said side and screw-threaded openings and metalterminal members having screw-threaded portions in said screwthreadedopenings and portions projecting through said transverse wall openingsin spaced relation to said element.

In testimony whereof, I have hereunto subscribed my name this 31st dayof March,

so 1927. I

WILLARD H. KEMPTON.

